1. Field of the Invention
This invention relates to an adsorption thermal storage apparatus and an adsorption thermal storage system including the apparatus. More particularly, this invention is concerned with the aforesaid apparatus and the thermal storage system particularly suitable for propelling the leveling of consumption of electric power by utilizing nighttime electric power.
2. Statement of Prior Art
Recent increase in demand for electric power is noticeable and it especially, poses a social problem that the demand for electric power shows a tendency to be concentrated in the daytime.
In order to cope with this tendency and to level off the utilization of electric power, so-called thermal storage systems have received attention in the field of air conditioning equipment for space heating or space cooling in which a refrigerator is run in the nighttime when the capacity of electric power is relatively replete to thereby store thermal energy, and the thermal energy is utilized in the form of cold (lower-temperature heat) and heat (higher-temperature heat) in the daytime when the demand for electric power is elevated.
Here, throughout the specification and claims, the terms, "cold" and "heat" are used to mean heat of a lower temperature and heat of a higher temperature, respectively, than the environmental temperature.
At the present time, known thermal energy storage systems include, for example, a water thermal storage system wherein thermal energy is stored by sensible heat of water, an ice thermal storage system wherein thermal energy is stored by the latent heat of melting ice, a thermal storage system utilizing a thermal storage material, etc.
Each of the thermal storage systems has both advantages and disadvantages, and consequently, these systems are utilized selectively and appropriately in accordance with the intended purposes.
However, a difficulty with the water thermal storage system is that in order to obtain required cold and heat, a large quantity of water is necessitated for thermal energy storage, and accordingly, is in need of a considerably huge thermal storage tank, as a result of which the overall system is made large-sized.
The ice thermal storage system doesn't require such a huge tank, but is forced to reduce appreciably the evaporation temperature of a refrigerator since thermal energy is stored in the form of ice at 0.degree. C. Because of this, the lowering of thermal storage efficiency is unavoidable. Furthermore, the system is not suited to equal thermal storage for cold and heat because the thermal storage quantity for heat is appreciably slight as compared with that for cold, being 1/4 to 1/5 time.
With the system utilizing a thermal storage material, the thermal storage material per se is considerably expensive and short in lifetime, and distinct thermal storage materials must be used for cold and heat, which makes the piping system complicated.
In order to solve the problems above with the existing thermal storage systems, this invention has been accomplished and is designed to provide an improved thermal storage apparatus and an ameliorated thermal storage system including 10 the apparatus, which system permits to make the overall system compact, to enhance the thermal storage efficiency when nighttime electric power is used, and to permit equalized thermal storage for cold and heat.